mm: hugetlb: cleanup using paeg_huge_active()

Now we have an easy access to hugepages' activeness, so existing helpers to
get the information can be cleaned up.

[akpm@linux-foundation.org: s/PageHugeActive/page_huge_active/]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hugh Dickins <hughd@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 13 insertions, 40 deletions

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 5713c49a4a5c..205026175c42 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -84,7 +84,6 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed);
 int dequeue_hwpoisoned_huge_page(struct page *page);
 bool isolate_huge_page(struct page *page, struct list_head *list);
 void putback_active_hugepage(struct page *page);
-bool is_hugepage_active(struct page *page);
 void free_huge_page(struct page *page);
 
 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
@@ -152,7 +151,6 @@ static inline bool isolate_huge_page(struct page *page, struct list_head *list)
         return false;
 }
 #define putback_active_hugepage(p)      do {} while (0)
-#define is_hugepage_active(x)   false
 
 static inline unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
                 unsigned long address, unsigned long end, pgprot_t newprot)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 84d10b65cec6..f34e040b34e9 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -470,11 +470,18 @@ static inline void ClearPageCompound(struct page *page)
 #ifdef CONFIG_HUGETLB_PAGE
 int PageHuge(struct page *page);
 int PageHeadHuge(struct page *page);
+bool page_huge_active(struct page *page);
 #else
 TESTPAGEFLAG_FALSE(Huge)
 TESTPAGEFLAG_FALSE(HeadHuge)
+
+static inline bool page_huge_active(struct page *page)
+{
+        return 0;
+}
 #endif
 
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 /*
  * PageHuge() only returns true for hugetlbfs pages, but not for
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 05407831016b..271e4432734c 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3896,20 +3896,6 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address,
 
 #ifdef CONFIG_MEMORY_FAILURE
 
-/* Should be called in hugetlb_lock */
-static int is_hugepage_on_freelist(struct page *hpage)
-{
-        struct page *page;
-        struct page *tmp;
-        struct hstate *h = page_hstate(hpage);
-        int nid = page_to_nid(hpage);
-
-        list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
-                if (page == hpage)
-                        return 1;
-        return 0;
-}
-
 /*
  * This function is called from memory failure code.
  * Assume the caller holds page lock of the head page.
@@ -3921,7 +3907,11 @@ int dequeue_hwpoisoned_huge_page(struct page *hpage)
         int ret = -EBUSY;
 
         spin_lock(&hugetlb_lock);
-        if (is_hugepage_on_freelist(hpage)) {
+        /*
+         * Just checking !page_huge_active is not enough, because that could be
+         * an isolated/hwpoisoned hugepage (which have >0 refcount).
+         */
+        if (!page_huge_active(hpage) && !page_count(hpage)) {
                 /*
                  * Hwpoisoned hugepage isn't linked to activelist or freelist,
                  * but dangling hpage->lru can trigger list-debug warnings
@@ -3965,25 +3955,3 @@ void putback_active_hugepage(struct page *page)
         spin_unlock(&hugetlb_lock);
         put_page(page);
 }
-
-bool is_hugepage_active(struct page *page)
-{
-        VM_BUG_ON_PAGE(!PageHuge(page), page);
-        /*
-         * This function can be called for a tail page because the caller,
-         * scan_movable_pages, scans through a given pfn-range which typically
-         * covers one memory block. In systems using gigantic hugepage (1GB
-         * for x86_64,) a hugepage is larger than a memory block, and we don't
-         * support migrating such large hugepages for now, so return false
-         * when called for tail pages.
-         */
-        if (PageTail(page))
-                return false;
-        /*
-         * Refcount of a hwpoisoned hugepages is 1, but they are not active,
-         * so we should return false for them.
-         */
-        if (unlikely(PageHWPoison(page)))
-                return false;
-        return page_count(page) > 0;
-}
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e2e8014fb755..457bde530cbe 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1373,7 +1373,7 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
                         if (PageLRU(page))
                                 return pfn;
                         if (PageHuge(page)) {
-                                if (is_hugepage_active(page))
+                                if (page_huge_active(page))
                                         return pfn;
                                 else
                                         pfn = round_up(pfn + 1,